El punto en el tiempo : Realismo y gran obra en Juan José Saer y César Aira

Fil: Sager, Valeria. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Chemical and isotope compositions of bottom sediments from ODP Leg 168, Eastern Flank of the Juan de Fuca Ridge

Ten sites were drilled in the eastern flank of the Juan de Fuca Ridge (North East Pacific) along a 100 km-long east-west transect during Leg ODP 168. This study focuses on the mineralogical and chemical study of sediments that overly basaltic basement through which seawater circulates. Silicate authigenesis was observed in the sediment layer just above basement at sites located more than 30 km from the ridge axis. This sediment alteration is particularly abundant at ODP Sites 1031 and 1029 where authigenic formation of Fe-Mg rich smectite and zeolite and the dissolution of biogenic calcite are observed. Comparison of the distribution of the alteration in the basal sediment collected along this transect suggests that diffusional transport of aqueous solutes from the basement into the overlying sediment cannot produce the mineralogical and chemical changes in the basal sediments at Sites 1031 located on a basement topographic high, and at Site 1029 located at about 50 km from the ridge axis on a buried basement area. Vertical advection of basement fluid though the sediment section is required to produce this alteration. These processes are still active at Site 1031, based on systematic variations in pore-water profiles and temperatures obtained from stable isotopic data on calcium carbonates and the nature of authigenic minerals. At Site 1029, there is no present-day advection of basement fluids though the sediment section, suggesting that this is a relic site for fluid flow.

Chemistry and age determination of basement fluids from Juan de Fuca Ridge

The geochemical implications of thermally driven flow of seawater through oceanic crust on the mid-ocean ridge flank have been examined on a well-studied 80 km transect across the eastern flank of the Juan de Fuca Ridge at 48°N, using porewater and basement fluid samples obtained on ODP Leg 168. Fluid flow is recognised by near-basement reversals in porewater concentration gradients from altered values in the sediment section to seawater-like values in basaltic basement. In general, the basement fluids become more geochemically evolved with distance from the ridge and broadly follow basement temperature which ranges from not, vert, similar16° to 63°C. Although thermal effects of advective heat exchange are only seen within 20 km east of where basement is exposed near the ridge crest, chemical reactivity extends to all sites. Seawater passing through oceanic crust has reacted with basement rocks leading to increases in Ca2+ and decreases in alkalinity, Mg2+, Na+, K+, SO42- and delta18O. Sr isotope exchange between seawater and oceanic crust off axis is unequivocally demonstrated with endmember 87Sr/86Sr ~ 0.707. Evidence of more evolved fluids is seen at sites where rapid upwelling of fluids through sediments occurs. Chlorinities of the basement fluids are consistent with post-glacial seawater and thus a short residence time in the crust. Rates of lateral flow have been by estimated by modelling porewater sulphate gradients, using Cl as a glacial chronometer, and from radiocarbon dating of basal fluids. All three methods reveal fluid flow with 14C ages less than 10,000 yr and particle velocities of ~1-5 m/yr, in agreement with thermally constrained volumetric flow rates through a ~600 m thick permeable layer of ~10% porosity. Delta(element)/Delta(heat) extraction ratios are similar to values for ridge-crest hydrothermal systems.

Minería aurífera a cielo abierto en Argentina : El caso del emprendimiento Veladero, provincia de San Juan

En los últimos diez años, nuestro país, y más precisamente la Cordillera de los Andes, ha sido el escenario de un marcado aumento de la actividad minera, tanto en lo que se refiere a tareas de exploración como de explotación. Los grandes proyectos orientados a la explotación de minerales metalíferos son los que impulsan este boom minero. Las razones más importantes que explican este acontecimiento son: el alto potencial minero de nuestro país, la profundización de las políticas neoliberales en la década de los 90, aumento del precio del oro en el mercado internacional, y el desplazamiento de actividades contaminantes desde los países centrales, hacia la periferia. Dentro de este contexto la provincia de San Juan ha tenido un rol preponderante como "capital nacional de la minería", promoviéndola como la "actividad productiva fundamental" para el crecimiento socio-económico provincial. Es en los partidos del noroeste de esta provincia donde la empresa canadiense Barrick Gold, la mayor empresa minera aurífera del mundo, emplazó en 2005 el emprendimiento Veladero, despertando, principalmente, el descontento entre los pobladores de los departamentos de Iglesia y Jáchal, y de distintas ONG abocadas a la problemática ambiental.

El problema de la representación en la poética de Juan José Saer

Fil: Merbilhaá, Margarita. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Gualeguay de Juan L. Ortíz

Fil: Páez, Roxana Haydée. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Democracia y contrarrevolución : Breve comentario a partir de la conferencia de Juan Carlos Portantiero

Fil: Bonavena, Pablo Augusto. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Entrevista a Juan José Saer

Fil: Merbilhaá, Margarita. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Juan Goytisolo, 2000. Carajicomedia de Fray Bugeo Montesino y otros pájaros de vario plumaje y pluma , Barcelona: Seix Barral, 249 pp.

Fil: Corbellini, Natalia. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Emilia Flores. Esquilo: Aristeia de los ojos en tragedia griega, U.N. San Juan, 2007, 304 pp.

Fil: Hamamé, Graciela Noemí. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.